From 49663bc483f424f26ffa18f8bfb2dba86395c699 Mon Sep 17 00:00:00 2001
From: Johann1994 <37308757+Johann1994@users.noreply.github.com>
Date: Wed, 18 Dec 2019 13:50:34 +0100
Subject: [PATCH 1/2] Sharedstringtable

Same strings in shared stringtable makes it not possible to open a xlsx file.
---
 source/workbook/workbook.cpp | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/source/workbook/workbook.cpp b/source/workbook/workbook.cpp
index fcea0b12..59f9a8af 100644
--- a/source/workbook/workbook.cpp
+++ b/source/workbook/workbook.cpp
@@ -1374,9 +1374,18 @@ std::size_t workbook::add_shared_string(const rich_text &shared, bool allow_dupl
         }
     }
 
-    auto sz = d_->shared_strings_ids_.size();
-    d_->shared_strings_ids_[shared] = sz;
+ 	//it can happen that similar strings are more then onetime in the shared stringtable (Excel bugfix?)
+	//shared_strings_values map should start on position 0
+	auto sz = d_->shared_strings_values_.size();
+    if (d_->shared_strings_values_.count(sz) > 0)
+    {
+        // something went wrong!
+        throw invalid_file("Error in shared string table!");
+	}
+
     d_->shared_strings_values_[sz] = shared;
+    d_->shared_strings_ids_[shared] = sz;
+
 
     return sz;
 }

From d6262df55583bd88f7bb402a01685a6dd5b1744e Mon Sep 17 00:00:00 2001
From: Johann1994 <37308757+Johann1994@users.noreply.github.com>
Date: Wed, 18 Dec 2019 13:53:23 +0100
Subject: [PATCH 2/2] Shared strings

It can happen that some strings are not unique in sharedstring table
---
 source/detail/serialization/xlsx_consumer.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/source/detail/serialization/xlsx_consumer.cpp b/source/detail/serialization/xlsx_consumer.cpp
index 2f29e19f..3fdbad1b 100644
--- a/source/detail/serialization/xlsx_consumer.cpp
+++ b/source/detail/serialization/xlsx_consumer.cpp
@@ -1923,13 +1923,15 @@ void xlsx_consumer::read_shared_string_table()
     {
         expect_start_element(qn("spreadsheetml", "si"), xml::content::complex);
         auto rt = read_rich_text(qn("spreadsheetml", "si"));
-        target_.add_shared_string(rt);
+		//by reading in it can happen we have similar strings from modified excel worksheets...
+		//so allow to add duplicates
+        target_.add_shared_string(rt, true);
         expect_end_element(qn("spreadsheetml", "si"));
     }
 
     expect_end_element(qn("spreadsheetml", "sst"));
 
-    if (has_unique_count && unique_count != target_.shared_strings().size())
+    if (has_unique_count && unique_count != target_.shared_strings_by_id().size())
     {
         throw invalid_file("sizes don't match");
     }